Field of the Invention
The invention relates generally to a device and method for agitating or mixing fluid within a container and, more particularly, to a clamp for securing the container to a mechanical agitator or shaker.
Description of the Related Art
Many types of fluid containers for holding and mixing fluid solutions in laboratory settings are known. These containers are used for a variety of applications, including metallurgy, textiles, cosmetics, government and education, food and beverage, chemicals, medical and biological testing. Use of such containers is widespread throughout the clinical, biotechnology, and pharmaceutical industries. Fluid containers are generally formed from a rigid transparent material such as glass or plastic, though containers made of metal are also used for some applications. The containers come in a variety of shapes and sizes depending on the particular use. Test tubes are simple graduated tubular containers for holding a small volume of fluid. Beakers and flasks are used for holding larger fluid volumes. A beaker is a generally cylindrical flat bottomed container. Flasks are available in a variety of shapes and sizes. An Erlenmeyer flask is a generally conical structure having angled sides, a flat bottom, and a narrow open end. Florence and round-bottom flasks have an elongated neck portion and a round bottom having a generally curved base. A volumetric flask is a teardrop-shaped container having an elongated neck portion, bulbous lower portion, and a substantially flat bottom.
In many applications, the contents of the fluid container must be mixed or agitated in a controlled and consistent manner for an extended period of time. Most simply, a user, such as a laboratory technician, student, or researcher, may use a stir rod or similar accessory to slowly stir the fluid solution. The user may also shake the container in an up and down or circular fashion to agitate the fluid contained therein. However, manually stirring or shaking a fluid container for an extended period of time is often tedious, imprecise, and difficult to reproduce, quantify, or document. Accordingly, various mechanical stirring, mixing, and agitating methods have been developed.
One common stirring method uses a metal slug placed in the fluid container. The container and slug contained therein are placed on a magnetized surface. The magnetized surface causes the slug to spin or rotate. Movement of the slug agitates the fluid within the container for continuous and reproducible mixing. However, for certain solutions, it is generally not preferable to place a slug in direct contact with the fluid itself. Therefore, alternative mixing and fluid agitation mechanisms are required.
One such alternative mixing mechanism is an orbital or platform shaker. Such shakers generally comprise a raised platform coupled to an automated driving mechanism. The container is placed on the platform to agitate fluid contained therein. Typically, orbital shakers are used with containers having a wide flat bottom that can sit independently on the moveable platform and will not tip over during agitation. For example, beakers and Erlenmeyer flasks are well-suited for use with a platform shaker. Racks and supports may be placed on the platform so that other containers, such as test tubes, round-bottom flasks, volumetric flasks, and the like can also be used with the shaker.
Hand motion shakers, which replicate a twisting motion of a wrist or arm, are also known. Such hand motion shakers are known by a variety of trade names including Wrist-Action®, Wrist-O-Matic, and Wrist-Motion, and are commercially available from several sources including Burrell Scientific and Fisher Scientific of Pittsburgh, Pa., Boekel Scientific of Feasterville, Pa., and Eberbach Corp. of Ann Arbor, Mich. A hand motion shaker includes a spindle coupled to a drive mechanism. The spindle is driven in a back and forth reciprocating motion that simulates radial movement of the wrist. Various connectors, grippers, clamps, clips, and stands are known for attaching a container to the spindle. For example, grippers can be used to grasp a portion of a beaker or flask to hold it in place as the spindle reciprocates. Racks or stands for holding a portion of a test tube are also known. Similarly, clips may be used to attach a flexible structure, such as a fluid bag, to the spindle. When the hand motion shaker is turned on, the spindle reciprocates in a back and forth motion, causing the container attached thereto to reciprocate back and forth. This motion agitates the fluid contained in the container to facilitate mixing. Some hand motion shakers allow a user to vary the reciprocation speed or range of reciprocation to adapt the agitation for a particular purpose. The reciprocation range is generally less than about 15 degrees.
Beneficially, hand motion shakers provide a continuous and gentle shaking motion that is useful for many laboratory applications. However, a hand motion shaker typically cannot be used with a flask with an elongated neck, such as a volumetric or round bottom flask. As described above, volumetric flasks have narrow elongate necks. The fluid is contained in the wider bulbous portion located below the neck. While grippers for attaching to the neck are known, such grippers are unable to properly brace the flask. Particularly, reciprocating motion creates an alternating bending moment at the contact between the grip and neck portion of the flask that can cause the neck portion of the flask to crack or break.
Therefore, there is a need for an enhanced clamp for use with a hand motion shaker. The clamp should be capable of supporting both the elongate neck portion and fluid containing bulbous portion of the flask. The clamp should be able to be used with a variety of standard sized flasks. The clamp should also be easy to manufacture and easily connected to existing hand motion shakers. Additionally, the clamp should be able to hold multiple flasks for simultaneous mixing using a single hand motion shaker.